package soot.jimple.infoflow;

import java.io.File;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import soot.FastHierarchy;
import soot.PackManager;
import soot.Scene;
import soot.SootClass;
import soot.jimple.infoflow.InfoflowConfiguration.CallgraphAlgorithm;
import soot.jimple.infoflow.cfg.BiDirICFGFactory;
import soot.jimple.infoflow.cfg.DefaultBiDiICFGFactory;
import soot.jimple.infoflow.cfg.LibraryClassPatcher;
import soot.jimple.infoflow.config.IInfoflowConfig;
import soot.jimple.infoflow.data.pathBuilders.IPathBuilderFactory;
import soot.jimple.infoflow.entryPointCreators.DefaultEntryPointCreator;
import soot.jimple.infoflow.entryPointCreators.IEntryPointCreator;
import soot.jimple.infoflow.handlers.PostAnalysisHandler;
import soot.jimple.infoflow.handlers.PreAnalysisHandler;
import soot.jimple.infoflow.ipc.DefaultIPCManager;
import soot.jimple.infoflow.ipc.IIPCManager;
import soot.jimple.infoflow.nativeCallHandler.DefaultNativeCallHandler;
import soot.jimple.infoflow.nativeCallHandler.INativeCallHandler;
import soot.jimple.infoflow.sourcesSinks.manager.DefaultSourceSinkManager;
import soot.jimple.infoflow.taintWrappers.ITaintPropagationWrapper;
import soot.options.Options;

/**
 * Abstract base class for all data/information flow analyses in FlowDroid
 * 
 * @author Steven Arzt
 *
 */
public abstract class AbstractInfoflow implements IInfoflow {

	private final Logger logger = LoggerFactory.getLogger(getClass());

	protected IPathBuilderFactory pathBuilderFactory;
	protected InfoflowConfiguration config = new InfoflowConfiguration();
	protected ITaintPropagationWrapper taintWrapper;
	protected INativeCallHandler nativeCallHandler = new DefaultNativeCallHandler();
	protected IIPCManager ipcManager = new DefaultIPCManager(new ArrayList<String>());

	protected final BiDirICFGFactory icfgFactory;
	protected Collection<? extends PreAnalysisHandler> preProcessors = Collections.emptyList();
	protected Collection<? extends PostAnalysisHandler> postProcessors = Collections.emptyList();

	protected final String androidPath;
	protected final boolean forceAndroidJar;
	protected IInfoflowConfig sootConfig;
	protected FastHierarchy hierarchy;

	/**
	 * Creates a new instance of the abstract info flow problem
	 */
	public AbstractInfoflow() {
		this(null, "", false);
	}

	/**
	 * Creates a new instance of the abstract info flow problem
	 * 
	 * @param icfgFactory     The interprocedural CFG to be used by the
	 *                        InfoFlowProblem
	 * @param androidPath     If forceAndroidJar is false, this is the base
	 *                        directory of the platform files in the Android SDK. If
	 *                        forceAndroidJar is true, this is the full path of a
	 *                        single android.jar file.
	 * @param forceAndroidJar True if a single platform JAR file shall be forced,
	 *                        false if Soot shall pick the appropriate platform
	 *                        version
	 */
	public AbstractInfoflow(BiDirICFGFactory icfgFactory, String androidPath, boolean forceAndroidJar) {
		if (icfgFactory == null) {
			DefaultBiDiICFGFactory factory = new DefaultBiDiICFGFactory();
			factory.setIsAndroid(androidPath != null && !androidPath.isEmpty());
			this.icfgFactory = factory;
		} else
			this.icfgFactory = icfgFactory;
		this.androidPath = androidPath;
		this.forceAndroidJar = forceAndroidJar;
	}

	@Override
	public InfoflowConfiguration getConfig() {
		return this.config;
	}

	@Override
	public void setConfig(InfoflowConfiguration config) {
		this.config = config;
	}

	@Override
	public void setTaintWrapper(ITaintPropagationWrapper wrapper) {
		taintWrapper = wrapper;
	}

	@Override
	public void setNativeCallHandler(INativeCallHandler handler) {
		this.nativeCallHandler = handler;
	}

	@Override
	public ITaintPropagationWrapper getTaintWrapper() {
		return taintWrapper;
	}

	@Override
	public void setPreProcessors(Collection<? extends PreAnalysisHandler> preprocessors) {
		this.preProcessors = preprocessors;
	}

	@Override
	public void setPostProcessors(Collection<? extends PostAnalysisHandler> postprocessors) {
		this.postProcessors = postprocessors;
	}

	@Override
	public void computeInfoflow(String appPath, String libPath, IEntryPointCreator entryPointCreator,
			List<String> sources, List<String> sinks) {
		this.computeInfoflow(appPath, libPath, entryPointCreator, new DefaultSourceSinkManager(sources, sinks));
	}

	@Override
	public void computeInfoflow(String appPath, String libPath, Collection<String> entryPoints,
			Collection<String> sources, Collection<String> sinks) {
		this.computeInfoflow(appPath, libPath, new DefaultEntryPointCreator(entryPoints),
				new DefaultSourceSinkManager(sources, sinks));
	}

	@Override
	public void computeInfoflow(String libPath, String appPath, String entryPoint, Collection<String> sources,
			Collection<String> sinks) {
		this.computeInfoflow(appPath, libPath, entryPoint, new DefaultSourceSinkManager(sources, sinks));
	}

	/**
	 * Appends two elements to build a classpath
	 * 
	 * @param appPath The first entry of the classpath
	 * @param libPath The second entry of the classpath
	 * @return The concatenated classpath
	 */
	private String appendClasspath(String appPath, String libPath) {
		String s = (appPath != null && !appPath.isEmpty()) ? appPath : "";

		if (libPath != null && !libPath.isEmpty()) {
			if (!s.isEmpty())
				s += File.pathSeparator;
			s += libPath;
		}
		return s;
	}

	/**
	 * Initializes Soot.
	 * 
	 * @param appPath The application path containing the analysis client
	 * @param libPath The Soot classpath containing the libraries
	 * @param classes The set of classes that shall be checked for data flow
	 *                analysis seeds. All sources in these classes are used as
	 *                seeds.
	 */
	protected void initializeSoot(String appPath, String libPath, Collection<String> classes) {
		initializeSoot(appPath, libPath, classes, "");
	}

	/**
	 * Initializes Soot.
	 * 
	 * @param appPath The application path containing the analysis client
	 * @param libPath The Soot classpath containing the libraries
	 * @param classes The set of classes that shall be checked for data flow
	 *                analysis seeds. All sources in these classes are used as
	 *                seeds. If a non-empty extra seed is given, this one is used
	 *                too.
	 */
	protected void initializeSoot(String appPath, String libPath, Collection<String> classes, String extraSeed) {
		// reset Soot:
		logger.info("Resetting Soot...");
		soot.G.reset();

		Options.v().set_no_bodies_for_excluded(true);
		Options.v().set_allow_phantom_refs(true);
		if (config.getWriteOutputFiles())
			Options.v().set_output_format(Options.output_format_jimple);
		else
			Options.v().set_output_format(Options.output_format_none);

		// We only need to distinguish between application and library classes
		// if we use the OnTheFly ICFG
		if (config.getCallgraphAlgorithm() == CallgraphAlgorithm.OnDemand) {
			Options.v().set_soot_classpath(libPath);
			if (appPath != null) {
				List<String> processDirs = new LinkedList<String>();
				for (String ap : appPath.split(File.pathSeparator))
					processDirs.add(ap);
				Options.v().set_process_dir(processDirs);
			}
		} else
			Options.v().set_soot_classpath(appendClasspath(appPath, libPath));

		// Configure the callgraph algorithm
		switch (config.getCallgraphAlgorithm()) {
		case AutomaticSelection:
			// If we analyze a distinct entry point which is not static,
			// SPARK fails due to the missing allocation site and we fall
			// back to CHA.
			if (extraSeed == null || extraSeed.isEmpty()) {
				setSparkOptions();
			} else {
				setChaOptions();
			}
			break;
		case CHA:
			setChaOptions();
			break;
		case RTA:
			Options.v().setPhaseOption("cg.spark", "on");
			Options.v().setPhaseOption("cg.spark", "rta:true");
			Options.v().setPhaseOption("cg.spark", "on-fly-cg:false");
			Options.v().setPhaseOption("cg.spark", "string-constants:true");
			break;
		case VTA:
			Options.v().setPhaseOption("cg.spark", "on");
			Options.v().setPhaseOption("cg.spark", "vta:true");
			Options.v().setPhaseOption("cg.spark", "string-constants:true");
			break;
		case SPARK:
			setSparkOptions();
			break;
		case GEOM:
			setSparkOptions();
			setGeomPtaSpecificOptions();
			break;
		case OnDemand:
			// nothing to set here
			break;
		default:
			throw new RuntimeException("Invalid callgraph algorithm");
		}

		// Specify additional options required for the callgraph
		if (config.getCallgraphAlgorithm() != CallgraphAlgorithm.OnDemand) {
			Options.v().set_whole_program(true);
			Options.v().setPhaseOption("cg", "trim-clinit:false");
			if (config.getEnableReflection())
				Options.v().setPhaseOption("cg", "types-for-invoke:true");
		}

		// do not merge variables (causes problems with PointsToSets)
		Options.v().setPhaseOption("jb.ulp", "off");

		setSourcePrec();

		// at the end of setting: load user settings:
		if (sootConfig != null)
			sootConfig.setSootOptions(Options.v(), config);

		// load all entryPoint classes with their bodies
		for (String className : classes)
			Scene.v().addBasicClass(className, SootClass.BODIES);
		Scene.v().loadNecessaryClasses();
		logger.info("Basic class loading done.");

		boolean hasClasses = false;
		for (String className : classes) {
			SootClass c = Scene.v().forceResolve(className, SootClass.BODIES);
			if (c != null) {
				c.setApplicationClass();
				if (!c.isPhantomClass() && !c.isPhantom())
					hasClasses = true;
			}
		}
		if (!hasClasses) {
			logger.error("Only phantom classes loaded, skipping analysis...");
			return;
		}
	}

	protected void setSourcePrec() {
		if (!this.androidPath.isEmpty()) {
			Options.v().set_src_prec(Options.src_prec_apk_class_jimple);
			if (this.forceAndroidJar)
				soot.options.Options.v().set_force_android_jar(this.androidPath);
			else
				soot.options.Options.v().set_android_jars(this.androidPath);
		} else
			Options.v().set_src_prec(Options.src_prec_java);
	}

	private void setChaOptions() {
		Options.v().setPhaseOption("cg.cha", "on");
	}

	private void setSparkOptions() {
		Options.v().setPhaseOption("cg.spark", "on");
		Options.v().setPhaseOption("cg.spark", "string-constants:true");
	}

	public static void setGeomPtaSpecificOptions() {
		Options.v().setPhaseOption("cg.spark", "geom-pta:true");

		// Those are default options, not sure whether removing them works.
		Options.v().setPhaseOption("cg.spark", "geom-encoding:Geom");
		Options.v().setPhaseOption("cg.spark", "geom-worklist:PQ");
	}

	@Override
	public void setSootConfig(IInfoflowConfig config) {
		sootConfig = config;
	}

	@Override
	public void setIPCManager(IIPCManager ipcManager) {
		this.ipcManager = ipcManager;
	}

	@Override
	public void setPathBuilderFactory(IPathBuilderFactory factory) {
		this.pathBuilderFactory = factory;
	}

	/**
	 * Constructs the callgraph
	 */
	protected void constructCallgraph() {
		// Allow the ICC manager to change the Soot Scene before we continue
		if (ipcManager != null)
			ipcManager.updateJimpleForICC();

		// Run the preprocessors
		for (PreAnalysisHandler tr : preProcessors)
			tr.onBeforeCallgraphConstruction();

		// Patch the system libraries we need for callgraph construction
		LibraryClassPatcher patcher = getLibraryClassPatcher();
		patcher.patchLibraries();

		// To cope with broken APK files, we convert all classes that are still
		// dangling after resolution into phantoms
		for (SootClass sc : Scene.v().getClasses())
			if (sc.resolvingLevel() == SootClass.DANGLING) {
				sc.setResolvingLevel(SootClass.BODIES);
				sc.setPhantomClass();
			}

		// We explicitly select the packs we want to run for performance
		// reasons. Do not re-run the callgraph algorithm if the host
		// application already provides us with a CG.
		if (config.getCallgraphAlgorithm() != CallgraphAlgorithm.OnDemand && !Scene.v().hasCallGraph()) {
			PackManager.v().getPack("wjpp").apply();
			PackManager.v().getPack("cg").apply();
		}

		// If we don't have a FastHierarchy, we need to create it
		hierarchy = Scene.v().getOrMakeFastHierarchy();

		// Run the preprocessors
		for (PreAnalysisHandler tr : preProcessors)
			tr.onAfterCallgraphConstruction();
	}

	protected LibraryClassPatcher getLibraryClassPatcher() {
		return new LibraryClassPatcher();
	}

}
